DESC:PULMONARY FLOW REGULATING DEVICE
TECHNICAL FIELD
[0001] The present invention relates to devices and methods for regulating and controlling blood flow into the lungs of mammalians. The present invention also relates to braided/stented Nitinol mesh based pulmonary flow regulating device with expanded Polytetrafluoroethylene (ePTFE) covering. Further, the invention relates to Nitinol mesh with memory retention properties. Further, the present invention specifically relates to pulmonary flow regulating device using braided/stented Nitinol mesh with ePTFE covering wherein the braided/stented Nitinol mesh comprising of memory retention properties.
BACKGROUND OF THE INVENTION
[0002] The primary function of a mammalian heart (human) is to provide oxygenated blood to organ systems of the body. Oxygenation is provided by sending deoxygenated blood returning to the heart through the blood vessel (pulmonary artery) to the lungs. To do this, the heart is divided into four chambers: two chambers in the right and two chambers in the left. The right upper collecting chamber (Right Atrium) receives deoxygenated blood and sends to the right sided pumping chamber (Right Ventricle) which is in turn connected to the pulmonary artery.
[0003] The oxygenated blood coming from the lungs to the left side of the heart (Left Atrium) sends blood to the Left sided pumping chamber (Left Ventricle) which in turn connects to the Aorta. Aorta distributes blood to all the organ systems through its branches. A person skilled in the art could understand the functions of the heart.
[0004] Heart defects are the most common birth defect accounting for approximating for 1 in 100 live births. As these defects are present since birth these are commonly known as Congenital Heart Defects or CHD. Some babies with CHD have excessive blood going into the lung making them breathless, unable to feed and grow. Regulating the blood flow to the lungs is paramount in managing children with this group of heart defects. Currently, the only method used for reducing blood flow to the lung is by putting a restrictive tie in the main pulmonary artery by surgically opening the breastbone.
[0005] In the developing countries, some common heart defects like holes in the heart (VSD) presents later in life when the time for direct closure is passed and need controlling the blood flow and reducing the pressure in the lung prior to major open-heart surgery.
[0006] US6638257B2 and US20030167068A1 teaches an intravascular flow restrictor comprises a braided tubular structure designed to be placed in the main pulmonary artery for limiting blood pressure in the lungs. The braided structure is designed to be collapsed for placement in a delivery catheter but when ejected from the delivery catheter, assumes a substantially larger diameter disk shaped device having one or more longitudinal channels or pass ways therethrough.
[0007] US7001409B2 teaches an intravascular flow restrictor comprises a braided tubular structure designed to be placed in the main pulmonary artery for limiting blood pressure in the lungs. The braided structure is designed to be collapsed for placement in a delivery catheter but when ejected from the delivery catheter, assumes a substantially larger diameter disk shaped device having one or more longitudinal channels or pass ways therethrough.
[0008] WO2007059594A1 teaches a pulmonary artery banding device comprising an inflating banding ring, to be installed around the patient pulmonary artery (PA), an extending tube, and an insufflating button,- said extending tube connecting insufflating button to the banding inflating ring, the banding ring being configured as a C-shape hydraulic sleeve forming a support for an inflating balloon, whose external wall is formed by a thin rigid silicon layer, and whose inside wall is formed by a thin flexible silicon layer, at the apart ends of the said banding ring two brims being disposed to facilitate the size banding adjustment according with th pulmonary artery calibre (PA); said banding ring being provided with holes for passage of sutures fixating the ring on the pulmonary artery of the patient; the insufflating button being configured as a cylindrical reservoir and being provided with holes for sutures.
[0009] Similarly, US8251067B2 teaches a flow control device for a bronchial passageway. The device can include a valve member that regulates fluid flow through the flow control device, a frame coupled to the valve member, and a membrane attached to the frame. At least a portion of the flow control device forms a seal with the interior wall of the bronchial passageway when the flow control device is implanted in the bronchial passageway. The membrane forms a fluid pathway from the seal into the valve member to direct fluid flowing through the bronchial passageway into the valve member.
[0010] Currently practised surgical banding of the pulmonary arteries is technically challenging as the band placement must be just enough to reduce the flow without distorting the pulmonary valve or main pulmonary artery or its branches. As this band is put outside the pulmonary artery, the degree of internal restriction achieved is difficult to judge, especially in ventilated babies who are paralysed under anaesthesia. The pressure and resistance in the lungs are very variable to oxygen and chemical composition of the blood. The patients will need post operative ventilation and long recovery based on the heart condition, degree of manipulation of the lungs and extend of surgical repair. Moreover, these patients will require de-banding and further surgical interventions which increases the morbidity and mortality due to repeated surgeries.
[0011] Even when a band is placed, achieving adequate tightness is demanding. This can be explained by the Poiseuille’s law which states blood flow is related to the fourth power of the radius of the vessel. Therefore, minor alteration in the diameter of the vessel will have a large impact on the pressure gradient and relative blood flow. In certain rare conditions, it is also needed to train a pumping chamber (left Ventricle) when it is connected to a low-pressure system like the pulmonary circulation (Congenitally corrected transposition of the great arteries or Mustard or Senning procedures).
[0012] By placing a flow regulator, a higher gradient is created between the Left Ventricle and the Pulmonary artery which enables the Left ventricle to pump into a circulation with higher resistance. The training process of the left ventricle especially in older patients may take months or may act as a permanent palliation. Due to the complexity of the procedure and the high morbidity and mortality associated with it is seldom performed. To deal with those problems, some researchers have endeavoured to create a banding device that allows postoperative diameter fine adjustment with no need for reinterventions, the so-called “adjustable PA banding devices” which is cumbersome and difficult to use.
[0013] Based on the foregoing, it is believed that a need exists for an improved pulmonary flow regulating device using braided/stented Nitinol mesh with ePTFE covering wherein the braided/stented Nitinol mesh comprising of memory retention properties, as described in greater detail herein.
SUMMARY OF THE INVENTION
[0014] The following summary is provided to facilitate an understanding of some of the innovative features unique to the disclosed embodiment and is not intended to be a full description.
[0015] It is, therefore, one aspect of the disclosed embodiments to provide for an improved pulmonary flow regulating device.
[0016] It is another aspect of the disclosed embodiments to provide for an improved braided/stented Nitinol mesh with ePTFE covering with memory retention properties.
[0017] It is further aspect of the disclosed embodiments to provide for an improved pulmonary flow regulating device using braided/stented Nitinol mesh with ePTFE covering wherein the braided/stented Nitinol mesh comprising of memory retention properties.
[0018] Pulmonary flow regulating device (100). The pulmonary flow regulating device (100) is constructed using braided/stented Nitinol mesh (110) with ePTFE covering (210) wherein the braided/stented Nitinol mesh (110) comprising of memory retention properties. The braided/stented Nitinol mesh (110) is heat treated to achieve the memory retention properties of the pulmonary flow regulating device (100). The ePTFE covering (210) provides restriction to the flow of blood to the pulmonary arteries thereby effectively controlling the flow of blood to the lungs of the mammalians (Human).
[0019] The pulmonary flow regulating device (100) with the Nitinol stented/braided wire mesh (110) is specifically shaped using memory metal properties to configure to the bifurcation of the pulmonary arteries and extending into the main pulmonary artery sparing the pulmonary valve. The device (100) is further covered with ePTFE (210) to provide restriction of flow into the pulmonary artery branches. The precise amount of flow to the branched pulmonary arteries will be determined by the size of the variable fenestration in the ePTFE (210) which will vary depending on the hemo-dynamics of the subject (patient) and complexity of the underlying heart disease. The device (100) has self-expansile memory properties which is predetermined based on the patient’s pulmonary artery and branching pattern wherein the device (100) can be delivered through a catheter placed in the main pulmonary artery using standard techniques that are well-known in the state-of-the-art.
DETAILED DESCRIPTION
[0020] The values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment and are not intended to limit the scope thereof.
[0021] The embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. The embodiments disclosed herein can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. As used herein, the term "and/or" includes all combinations of one or more of the associated listed items.
[0022] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0023] Invention: Pulmonary flow regulating device (100). FIG. 1 illustrates the graphical representation of the pulmonary flow regulating device (100) which is constructed using braided/stented Nitinol mesh (110) with ePTFE covering (210) wherein the braided/stented Nitinol mesh (110) comprising of memory retention properties. The braided/stented Nitinol mesh (110) is heat treated to achieve the memory retention properties of the pulmonary flow regulating device (100). The ePTFE covering (210) provides restriction to the flow of blood to the pulmonary arteries thereby effectively controlling the flow of blood to the lungs of the mammalians (Human).
[0024] The pulmonary flow regulating device (100) with the Nitinol stented/braided wire mesh (110) is specifically shaped using memory metal properties to configure to the bifurcation of the pulmonary arteries and extending into the main pulmonary artery sparing the pulmonary valve. The device (100) is further covered with ePTFE (210) to provide restriction of flow into the pulmonary artery branches (FIG. 2). The precise amount of flow to the branched pulmonary arteries will be determined by the size of the variable fenestration in the ePTFE (210) which will vary depending on the hemo-dynamics of the subject (patient) and complexity of the underlying heart disease. The device (100) has self-expansile memory properties which is predetermined based on the patient’s pulmonary artery and branching pattern wherein the device (100) can be delivered through a catheter placed in the main pulmonary artery using standard techniques that are well-known in the state-of-the-art (FIG.3).
[0025] Working of the Invention: The device (100) has a profile/shape which is unique as it fixes the branching pattern of the main pulmonary artery with a T shape configuration with each end extending into the branched pulmonary artery and the central portion extending into the main pulmonary artery positioned just above the pulmonary valve cast. As shown in FIG. 1, the shape, size and configuration of the Nitinol mesh will be individualized to be patient specific and matched to the dimensions of the pulmonary arteries derived from advanced imaging like CT/MRI of the patients.
[0026] The advance technology used in the construction of the ePTFE (210) does not interfere with the expansion of the Nitinol to the preconfigured shape and the tensile strength is adjusted to the diameter of the pulmonary artery providing secure placement. The uncovered area on both ends of the device (100) is adjusted to the flow requirement to optimise pulmonary blood flow. The configuration of the device (100) is such that it can be delivered through a 4-6 French delivery system to enable interventions in premature neonates to adults.
[0027] The device (100) is designed to restrict flow within the vessel wall it is expected that the device (100) will be causing less damage to the vessel wall and can be retrieved safely at the time of surgery. As the device (100) is intraluminal the usual fibrosis and scarring and resultant narrowing seen with PA Band and long-term consequences of balloon expandable stents are unlikely to result from the present device (100).
[0028] Alternative Embodiments: In another embodiment of the present invention, the device (100) instead of ePTFE covering (210), any other covering material can be alternatively used such as Dacron or bioabsorbable materials like Polylactate or similar scaffoldings. In one more embodiment of the present invention, the device can involve an extension of the self-expansile stent from the branched pulmonary arteries into the descending aorta through a persistent arterial duct to provide continuous support of systemic blood flow through the pulmonary arteries as in the case of complex coarctation or hypoplastic left heart syndrome variant. In alternative embodiment of the present invention, the variation of the openings maybe further expanded with balloon or stent dilatation to provide increased blood flow to the lungs based on somatic growth. This would act as an adjustable flow regulator to pulmonary blood flow.
[0029] Summary of the Invention: The present invention is based on the normal anatomy of the pulmonary artery and its branches and calculated diameters at various ages using standard calculation methods and approaches. The invention is based on the memory retention property of Nitinol mesh (110) by heat treatment into a predetermined shape and size. Covering such a pre-shaped device with an ePTFE membrane (210) allows specified diameter opening in the device at preferred angles and size to regulate the flow through the device (100).
[0030] Such an opening could vary depending on the size of the patient’s diameter of the pulmonary artery underlying hemodynamic variables and degree of restriction to flow required. This would range normally between 2.5mm and 10mm. Placing such a device by trans-catheter interventional technique could provide regulation of pulmonary blood flow in patients of any age group. Such a device could be placed through the inferior vena cava (IVC) through femoral venus approach, trans-jugular approach.
[0031] It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also, that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
,CLAIMS:I/We Claim:
1. A pulmonary flow regulating device, comprising of
a pulmonary flow regulating device (100) constructed using braided/stented Nitinol mesh (110) with ePTFE covering (210) wherein the braided/stented Nitinol mesh (110) comprising of memory retention properties wherein the pulmonary flow regulating device (100) with the Nitinol stented/braided wire mesh (110) is specifically shaped using memory metal properties to configure to the bifurcation of the pulmonary arteries and extending into the main pulmonary artery sparing the pulmonary valve.
2. The device as claimed in claim 1 wherein the braided/stented Nitinol mesh (110) is heat treated to achieve the memory retention properties of the pulmonary flow regulating device (100).
3. The device as claimed in claim 1 wherein the ePTFE covering (210) provides restriction to the flow of blood to the pulmonary arteries thereby effectively controlling the flow of blood to the lungs of the mammalians (Human).
4. The device as claimed in claim 1 wherein the ePTFE (210) provides restriction of flow into the pulmonary artery branches wherein the precise amount of flow to the branched pulmonary arteries will be determined by the size of the variable fenestration in the ePTFE (210) which will vary depending on the hemo-dynamics of the subject (patient) and complexity of the underlying heart disease.
5. The device as claimed in claim 1 wherein the device (100) has self-expansile memory properties which is predetermined based on the patient’s pulmonary artery and branching pattern wherein the device (100) can be delivered through a catheter placed in the main pulmonary artery.
6. The device as claimed in claim 1 wherein an extension of the self-expansile stent from the branched pulmonary arteries into the descending aorta through a persistent arterial duct to provide continuous support of systemic blood flow through the pulmonary arteries as in the case of complex coarctation or hypoplastic left heart syndrome variant.
7. The device as claimed in claim 1 wherein the variation of the openings may be further expanded with balloon or stent dilatation to provide increased blood flow to the lungs based on somatic growth which can act as an adjustable flow regulator to pulmonary blood flow.